FIG. 1 illustrates a conventional peripheral bus architecture. A plurality of devices communicates via the peripheral bus 100 according to a standard, such as the Peripheral Component Interface (PCI) standard. The PCI standard is well known in the art. In this specification, “PCI” refers to both PCI and PCI-X bus standards. A host bridge 102 arbitrates access to the peripheral bus 100 for a plurality of peripheral bus-compliant devices and provides an access path between these devices and the host processor 120. A controller 112 on a peripheral bus adapter 110 couples to a peripheral bus connector 108 and accesses the bus 100 through the connector 108. The controller 112 manages the bus-compliant device 104 and its control circuit 106.
FIG. 2 illustrates the pins of a conventional peripheral bus connector. Assuming that the connector 108 is a PCI connector, it has a set of pins 202 for 32-bit transfers, and a set of extension pins 204 for 64-bit transfers.
Occasionally, it is desirable to extend the capabilities of the device 104. One manner of extending the capabilities is to upgrade from the device's controller 112 to a more advanced controller 118 on another peripheral bus adapter 116 coupled at another peripheral bus connector 114. However, this adds to the cost of the system since the original controller 112 typically sits idle once the new controller 116 is installed.
Another manner of extending the capabilities of the device 104 is to aggregate its resources using one controller 112 at one connector 108, but by redefining one or more of the signals that is standard for the peripheral bus 100. However, when the signals are redefined, the controller 112 and the connector 108 cease to function according to the standard, making the system less flexible.
Accordingly, there exists a need for improved aggregation of resources across a peripheral bus. The improved resource aggregation should allow the controller of the device to aggregate its resources without redefining standard signals. The present invention addresses such a need.